This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objectives of this phase II, open-label, multi-center study are to determine whether the quadrivalent HPV vaccine is immunogenic, safe, and well-tolerated in 16- to 23-year-old HIV-infected young women, and to examine whether vaccination impacts their perceptions of risk and sexual behaviors.